1. Field of the Invention
The present invention relates to a nonvolatile semiconductor memory device having a plurality of memory cells which are connected in series and in particular, is related to a NAND flash memory device.
2. Description of the Related Art
As a semiconductor memory device there is a device which is cited in Japan patent application KOKAI publication No. 2002-203395. This semiconductor memory device is arranged with a booster circuit which includes oscillation means which generates two types of clock signal with different frequencies in response to a selection signal of an external input, and boosting means which conducts a boost operation at drive power in response to a clock signal from oscillation means. Because two types of clock signals with different frequencies are used only at the data program operation and the erasure operation in this semiconductor memory device, the power-consumption increases during data read operation.